Line a 12-cup muffin tin with paper liners or spray with nonstick baking spray that contains flour.
In a medium bowl, whisk together 2 ½ cups flour, baking powder, kosher salt, cinnamon, and nutmeg.
2 1/2 cups All-purpose flour, 1 1/2 tsp Baking powder, 1 tsp Kosher salt, 2 1/2 tsp Ground cinnamon, 1/2 tsp Ground nutmeg
In a large bowl, whisk together the sugar and eggs until thick and pale, about 1 minute. Slowly whisk in the melted butter until combined. Add buttermilk and vanilla extract and stir until smooth.
1/2 cup Granulated sugar, 1/2 cup Dark brown sugar, 2 large Eggs, 1/2 cup Unsalted butter, 1 cup Buttermilk, 1 1/2 tsp Vanilla extract
Gently fold the dry ingredients and shredded zucchini into the wet mixture until just combined. Do not over mix—some lumps and streaks of flour are okay. Cover the bowl with plastic wrap and let the batter rest for 15 minutes while you preheat the oven to 425°F (218°C).
2 cups Fresh zucchini
Divide the batter evenly among the muffin cups using a scoop. Bake for 15–20 minutes, or until golden brown and a toothpick inserted into the center comes out clean. Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.